We have the last ice age to blame—or thank, if yours is a generous spirit—for the hills of Brooklyn. Through the Pleistocene Epoch, continental ice sheets expanded and retreated dozens of times, carrying and smoothing rocks and eventually depositing them miles from where they had been picked up. The Laurentide ice sheet, which covered much of Canada and the northern United States, reached its greatest extent in the most recent glacial period about 20,000 years ago. Its southernmost boundary crossed Brooklyn.

Read More